function s1_goto_dir(){
cd "$1"
}
function s2_touch_empty_file_with_given_name(){
touch "$1"
}
function s3_make_directories(){
mkdir -p projects/git projects/backup
}
function s4_create_6_files(){
touch projects/{linux1_,linux2_}{centos,redhat,c_programming}
}
function s5_make_directories_in_git(){
mkdir -p projects/git/{linux1,linux2}
}
function s6_move_files_to_dir_1_or_2(){
mv projects/linux1_* projects/git/linux1/ && mv projects/linux2_* projects/git/linux2/
}
function s7_create_packge_and_compress(){
tar -czvf projects/backup/git.tar.gz -c ~/projects git/
}
function s8_delete_dir_git(){
rm -rf ~/projects/git
}
function s9_recover_from_git_tar_gz_backup(){
rm -rf ~/projects/git
}
function s10_create_package_and_compress(){
tar -jcvf projects/backup/git.tar.bz2 ~/projects git/
}
function s11_find_and_sort_alphabetically_all_created_files_and_dirs(){
find ./projects -type f -o -type d | sort
}
function s12_get_next_15_minutes_boundary(){
date + '%Y-%m-%d_%H:%M:%S'-d@$(($(date +%s)/900*900+900))
}

